Anatase phase TiO2 thin films obtained by pulsed laser deposition for gas sensing applications

Anatase phase titanium dioxide (TiO2) thin films were grown by pulsed laser deposition on h0 0 1i SiO2 substrates. An UV KrF* (l = 248 nm, tFWHM ffi 20 ns, n = 2 Hz) excimer laser was used for the irradiation of the TiO2 targets. The substrates were kept at room temperature or heated during the film deposition at values within the 100–500 8C range. The crystalline quality of the films and their chemical composition were investigated by X-ray diffractometry and energy dispersive X-ray spectroscopy. The optical properties were studied by a double beam spectrophotometer in the spectral range of 400–1200 nm. At substrate temperatures higher than 300 8C, the structure of the deposited thin films changes from poorly to well crystallised, corresponding to the tetragonal TiO2 anatase phase. The average optical transmittance in the visible-infrared spectral range of the films is higher than 85% which makes them suitable for sensor applications